Here you go, Piston area and force.

More piston area does not automatically mean more force on the rod!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

If more air air is drawn into the cyl as a result of an increase in piston area, then more air is compressed & more force is applied to the piston. If more air was drawn in as a result of a longer stroke, then the same force is applied to the crank whether the piston area was small or large. The small piston will have greater loading [ more lbs/ per sq in ].
More piston area only increases 'push' on the conrod if a secondary event such as ingesting more air occurs that increases the 'push' medium, the medium in this case being more force generated by the expanding hot burning mixture.

Here is yet another example: the claim is that increased piston area will create more 'push' on the con rod. The force on the piston is transmitted to the crank via the conrod & through the piston pin to the rod. Using the same 'logic', if I double the pin/rod contact area, the rod will 'push' harder on the crank!!